1. Field of the Invention
The present invention relates to a rolling piston type compressor and more. More particularly, relates to a low pressure container type rolling piston compressor having an improved oil supplying means.
2. Discussion of the Background
FIG. 8 shows a conventional rolling piston type compressor disclosed in, for instance, Japanese patent application No. 161299/1988. In FIG. 8, reference numeral 1 designates a sealing container, numeral 2 designates a cylinder disposed in the sealing container 1, numeral 3 designates a rotary shaft arranged at the axial center of the cylinder 2 and having an eccentric shaft portion, numeral 4 designates a frame or a first bearing plate arranged at an end portion of the cylinder, numeral 5 designates a cylinder head or a second bearing plate arranged at the other end portion of the cylinder, numeral 6 designates a rotor, or a rolling piston revolving in the cylinder 2 in an eccentric manner, numeral 7 designates a low pressure chamber defined by the cylinder and the other elements, numeral 8 designates high pressure chamber, a numeral 9 designates a vane for dividing the inside of in the cylinder into the low pressure chamber and the high pressure chamber, numeral 10 designates a discharge muffler, numeral 11 designates a gear pump for supplying oil, numeral 12 designates a motor element, and numeral 13 designates lubricating oil.
The operation of the conventional rolling piston compressor will now be described.
When the rotary shaft 3 is driven by the motor element 12, oil is supplied from the gear pump 11 placed at an end portion of the rotary shaft 3 to the frame 4 of the rotary shaft 3, bearing portions of the cylinder head 5 and the inner circumferential portion of the rotor 6. Since the rotor 6 is rotated eccentrically in the cylinder 2 and the vane 9 is always in pressing-contact with the rotor 6, the low pressure chamber 7 and the high pressure chamber 8 are formed in the cylinder 2. Gas introduced from the intake pipe (not shown) or the sealing container 1 to the low pressure chamber 7 is compressed, and the compressed gas is discharged through the high pressure chamber 8 to be discharged through a high pressure pipe extending outside the sealing container 1 via the discharge muffler 10 and a discharge pipe (not shown).
In the conventional rolling piston compressor having the above-mentioned construction, a sufficient oil supply is obtained to the bearing portions for supporting the rotary shaft 3. In the case of a high pressure container type compressor, oil supply to the low pressure chamber 7 and the high pressure chamber 8 in the cylinder 2 is conducted by supplying oil through gaps between the structural elements and the rotor 6. However, in the low pressure container type compressor, the pressure of the inner space of the rotor 6 is always lower than that of the high pressure chamber 8 and is the substantially same as that of the low pressure chamber 7. Accordingly, oil supply through the gaps between the rotor 6 and the other structural elements can not be substantially obtained. Therefore, the sealing function in the compressor is decreased. This causes leakage of pressurized gas to increase, performance to be reduced and a use in temperature at the contacting surface between the rotor 6 and the vane 9.